Educational appliance.



nann .DE wir'r IDE sneer, or conrnann, roan.

EDUCATIONAL APPLIANCE.

LZattlatlSL Specification of Letters Patent.

Patented @ept. ilil, 191"? Application filed April 2, 1914. Serial No. 829,833.

To all whom it may concern:

Be it known that I, HARRY DE Wrr'r DE GRoA'r, of Cortland, in the county of Cortland, in the State of New York, have 1nvented new and useful Improvements 1n Educational Appliances, of which the following, taken in connection with the accompanying drawings, is a full, clear, and exact description.

This invention relates to certain improve ments in apparatus for drilling students orally in mental mathematical calculations involving the use of one or more plates or charts bearing a multiplicity of numerals to be mentally correlated in various comblnations from which different quantitative results may be deduced.

The main object is to stimulate interest and quicken the ability of the student 1n accurate mental deductions from such combinations by placing a carefully selected variety of numerals in such relation that they may all be visible at once and the varlous combinations mentally segregated and computed in rapid succession.

Another object is to assemble a series of these plates or cards in compact relation and in such manner that they maybe successively reversed or displaced when it is desired to present new or different groups of mathematical problems with-out seriously interrupting the drilling process or distracting the mind of the student.

A. further object is to'provide movable means for temporarily obscuring one or another of the factors of any one of the groups or problems so that the student may be drilled in different combinations of the same group.

Other objects and uses will be brought out in the following description.

In the drawings-- Figures 1, 2 and 3 are face views of one form of apparatus for carrying out my improved method of instruction showing modified forms of shutters for temporarily obscuring one or the other of the factors of the several groups.

Figs. 4 and 5 are transverse sectional views taken respectively on lines 4-4 and 5-5, Fig. 2.

Fig. 6 is an edge view of the device shown in Fig. 8, the dotted lines indicating the displaced position of one of the plates.

Figs. 7 and 8 are face views of similar devices showing a plurality of narrower plates arranged side by side and bearing different groups of numerals for different branches of mathematics.

The apparatus shown in Figs. '1 to 6 in elusive comprises a back-board or main supporting frame 1- of wood, metal, cardboard, or other suitable material having on its upper end an eyelet -2 by which it may be hung or suspended in an upright position upon a wall-nail or equivalent fastening means (not shown).

Movably mounted upon this back-board in superposed relation is a plurality of number plates or cards 8, constituting a series of arithmetical charts each bearing upon one or both faces a plurality of groups or rows iof numerals printed or otherwise impressed thereon, those of each group being different from those of the other groups and carefully selected to'present the most practical problems for mental computations according to the judgment of the instructor or capabilities of the students.

The numerals of these particular groups are the factors or terms of proportions for disciplining the mind in ratios and equalities of ratios of quantities and costs or any other values and are adapted to be mentally segregated and inter-chan ed in various combinations with one or the other of the factors temporarily ignored or obscured for mental deduction or computation.

For example, taking the first or top row or group of numerals and mentally combining the quantitative number 5 and the cost number 20 of that quantity to find the cost of a unit quantity, the result 4 is a problem in mental division or from the same group may be combined the quantitative numeral 5, the cost numeral 20 and the other quantitative numeral 8 to find the cost 32 of the latter which involves problems both in division and multiplication.

Again from the same group the quanti tative numerals 5 and 8 and the cost numeral 20 may be combined to find the cost of the sum of the quantities 5 and 8 or 13 which would be 52 and involves mental problems in division, addition and multiplication. Or, taking the same group to find the cost of the difference -3 between the quan-- titative values would involve problemsjin division, subtractlon and multiplication. a

It is also evident that from the same be determined mentally as 25%, thereby introducing problems in percentage.

From these examples, it will be seen that similar problems in addition, substraction, nm-ltiplication, division, ratios, proportions, fractions and percentage may be selected and mentally computed from any one of the different groups on the same face-of the front card without changing its position or performing any other operation which might distract the mind of the student from continued application to those problemsand that any number of similar cards bearing additional groups of numerals of different relative values may be employed for carrying on the process of drilling in various branches of mathematics.

One convenient method of successively displaying the several cards as the work of mental training progresses is to hinge them by binding their lower edges together as shown at -a or by any other equivalent means which will allow them to be swung downwardly one at a time below their normal plane with the least possible effort sufiiciently to expose the numerals on the front face. of the subjacent plate and to provide suitable means as a retainer bar -72 secured to the back-board and portions thereof spaced apart from said board to permit the insertion and withdrawal of the upper ends of the cards into and from such space which may be accomplished by simply springing the body of the cards outwardly until their upper ends are clear from the retaining bar.

As shown the ends and central portion of the bar are secured to the backboard so as to form two loops b, the

a single series of cards with separate tongues for entering said loops as shown in Figs. 1, 2 and 3, or a double series of cards as shown in Figs. 7 and 8.

. In Figs. '2 and -3, I have shown modified .forms'of shutters -0-and (Z for temporarily covering and obscuring such numerals of the several groups as may be desired to represent the unknown. value to bev mentally computed from the remaining numerals of such groups, the shutter -0 consisting of a bar of metal or other opaque material h-ingedly mounted on suitable pintles -eon either edge of the back-board -1 so as to be swung across and from the front side of the plates or transferred from one set of pintles to the other, said bar being qorovided with=oppositely projecting sets of tongues 0-, those of each set being spaced apart andarranged instaggered re- :lation to those of the other setso that the tongues on one side will cover alternate numerals in one colunm, leaving the remaining numerals of that column exposed through the spaces, while lthe=tongues on the other side w1ll cover alternate immerals in another column leaving the remaining nu-v with reference to the numerals in thejother two columns. ,7 i

The shutter bar cZ.- may also be formed of any opaque'fiat material of substantially the width of 0116 of the columns and is preferably hinged toand slidable along a transverse rod ,7 on the upper end of the back-board so as to be swung upwardly out of'the way or moved laterally to cover the numerals in any one of the columns accordthe student in fractions in which one of the factors is unknown and represented by a question mark-t?) to be computed, while in Fig. 8 eachset of cards bears a single column of numerals arranged opposite each other to form groups calculated to discipline the mind in quickly solving rudimentary problems in addition, subtraction and multiplication, the numerical results beingomitted for mentaldeduction;

When the'cards are mounted on'the backboards in the manner described, the ones adjacent their respective back-boards are preferably attached thereto by one or more clips gwhich may be removed or re- ,placed' at will to permit the substitution of different sets 'of cards when desired; V H

An educationalapplianceof this-character "is particularly useful and efficient not only as an aid to the teacher in clearly imparting rudimentary arithmetic to students but also permanently fixes in the mind of the student the principles involved in such rudiments and enables all students to solve numerical problems easily, quickly and accurately.

What I claim is:

1. In an educational appliance of the character described, the combination of a relatively stiff back plate, a series of relatively flexible reversible charts arranged flatwise upon the front face of said plate, means for detachably pivotally attaching the lower edges of the charts to said plate,

means for detachably holding the upper ends of the charts in position adjacent the back plate to permit the intermediate portion of the front chart to be sprung forwardly to withdraw the upper end from beneath the holding means for displacement of said front chart for reversibility thereof and exposure of the one adjacent thereto.

2. In an educational appliance of the character described, the combination of a relatively stiff back plate, a series of relatively flexible charts arranged fiatwise upon the front face of said plate carrying printed matter on opposite sides thereof, means for detachably pivotally attaching the lower edges of the chart to said plate, a guard carried by the upper end of the back plate and having portions spaced from the front wall thereof between which the upper ends of the charts are loosely inserted, thus permitting the intermediate portion of the front chart to be sprung forwardly to withdraw the upper end from beneath the guard for displacement of the front chart and exposure of the one adjacent thereto.

3. In an educational appliance of the character described, the combination of a relatively stiff back plate, a series of relatively flexible reversible charts arranged flatwise upon the front face of said plate, means for detachably pivotally attaching the lower edges of the charts to said plate, means for detachably holding the upper ends of the charts in position adjacent the back plate to permit the intermediate portion of the front chart to be sprung forwardly to withdraw the upper end from beneath the holding means for displacement of said front chart for reversibility thereof and exposure of the one adjacent thereto and a relatively narrow shutter hinged at its upper end to said holding means slidable transversely of the back plate to conceal chosen portions of the uppermost chart.

In witness whereof I have hereunto set my hand this th day of March 1914.

HARRY DE WITT DE GROAT.

Witnesses:

HARRY E. REED, ROY B. KELLEY.

flopies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

. Washington, D. 0. 

